[class.copy.elision] Add cross-reference, fix example.

Author: jensmaurer

source/classes.tex

@@ -6594,7 +6594,8 @@
 an rvalue reference to a non-volatile object type.
 In the following copy-initialization contexts, a move operation might be used instead of a copy operation:
 \begin{itemize}
-\item If the \grammarterm{expression} in a \tcode{return} or \tcode{co_return} statement\iref{stmt.return}
+\item If the \grammarterm{expression} in a \tcode{return}\iref{stmt.return} or
+\tcode{co_return}\iref{stmt.return.coroutine} statement
 is a (possibly parenthesized) \grammarterm{id-expression}
 that names an implicitly movable entity declared in the body
 or \grammarterm{parameter-declaration-clause} of the innermost enclosing
@@ -6660,20 +6661,22 @@
 \pnum
 \begin{example}
 \begin{codeblock}
-void f() {
+template<class T> void g(const T&);
+
+template<class T> void f() {
   T x;
   try {
     T y;
     try { g(x); }
     catch (...) {
       if (/*...*/)
-        throw x;                // does not move
-      throw y;                  // moves
+        throw x;        // does not move
+      throw y;          // moves
     }
     g(y);
   } catch(...) {
     g(x);
-    // g(y); // error
+    g(y);               // error: \tcode{y} is not in scope
   }
 }
 \end{codeblock}